Twist–Bend Nematic Phase Behavior of Cyanobiphenyl-Based Dimers with Propane, Ethoxy, and Ethylthio Spacers
نویسندگان
چکیده
The twist–bend nematic (NTB) phase is a liquid crystal (LC) with heliconical structure that typically forms below the temperature of conventional (N) phase. By contrast, direct transition between NTB and isotropic (Iso) phases without intermediation N rarely occurs. Herein, we demonstrate effects linkage type (i.e., methylene, ether, thioether) on typical Iso–N–NTB rare Iso–NTB phase-transition behaviors cyanobiphenyl (CB) dimers CB3CB, CB2OCB, CB2SCB bearing three-atom-based propane, ethoxy, ethylthio spacers, respectively. In our previous study, exhibited monotropic transition. this report CB3CB also shows transition, whereas CB2OCB exhibits sequence decreasing temperature. Iso–LC (Iso–NTB or Iso–N) temperatures upon cooling show order (108 °C) > (49 (43 °C). thioether-linked vitrifiable, exhibit strong crystallization tendencies. are discussed in terms three bent homologous series different oligomethylene spacers n: CBnCB, CBnOCB, CBnSCB.
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ژورنال
عنوان ژورنال: Crystals
سال: 2022
ISSN: ['2073-4352']
DOI: https://doi.org/10.3390/cryst12121734